Pick what you want running and for how long. See what it takes to back it up: battery, sun and generator.
From the calculator on this page, using typical appliances and a 20% driving reserve. Updated November 3, 2026.
Twelve everyday setups, worked out with the same math as the calculator. Tap any one to load it, then change it to fit your house.
The essentials means the fridge, lights, Wi-Fi and phones, TV, two fans, microwave and coffee maker. kWh (kilowatt-hour) is the unit on your power bill: a 1,000-watt microwave running for one hour uses 1 kWh.
Running: Fridge, lights, Wi-Fi and phones, for 1 day.
Power: A 48-volt lithium golf cart battery (about 5 kWh), 20% kept for driving; no solar; no generator.
Yes. The battery lasts about 1.4 days, more than the 1 day you need.
Uses 2.8 kWh a dayPeak 1,360 watts
Running: The essentials, for 3 days.
Power: A 48-volt lithium golf cart battery (about 5 kWh), 20% kept for driving; no solar; no generator.
The battery lasts most of a day. For longer, add a generator, more battery or a shorter list.
Uses 4.9 kWh a dayPeak 3,660 watts
Running: The essentials, for 7 days.
Power: A 48-volt lithium golf cart battery (about 5 kWh), 20% kept for driving; no solar; a 5,000-watt portable generator.
The battery lasts most of a day. After that, the generator runs about 1.9 hours a day to keep up, instead of 24.
Uses 4.9 kWh a dayPeak 3,660 wattsGenerator: 1.9 hrs a day
Running: A CPAP, fridge, lights, Wi-Fi and phones, for 7 days.
Power: A 48-volt lithium golf cart battery (about 5 kWh), 20% kept for driving; no solar; a small 2,200-watt portable generator.
Yes, with the generator. The battery lasts about 1.2 days. After that, the generator runs about 2.2 hours a day to keep up, instead of 24.
Uses 3.2 kWh a dayPeak 1,410 wattsGenerator: 2.2 hrs a day
Running: The essentials, for 7 days.
Power: A 48-volt lithium golf cart battery (about 5 kWh), 20% kept for driving; a two-truck solar carport (about 7.5 kW), in mixed sun and clouds; no generator.
Yes. On days like that, the sun puts back more than you use, so it keeps going as long as the weather holds and the solar is built to keep working in an outage.
Uses 4.9 kWh a dayPeak 3,660 watts
Running: The essentials, for 7 days.
Power: An electric pickup with a standard battery (about 100 kWh), 20% kept for driving; no solar; no generator.
The battery lasts about 15 days.
Uses 4.9 kWh a dayPeak 3,660 watts
Running: The essentials, plus one window A/C, for 7 days.
Power: An electric pickup with a standard battery (about 100 kWh), 20% kept for driving; no solar; no generator.
Not for 7 days. The battery lasts about 6 days. For longer, add a generator, more battery or a shorter list.
Uses 12.1 kWh a dayPeak 4,810 watts
Running: The essentials, plus one window A/C, for 14 days.
Power: An electric pickup with a standard battery (about 100 kWh), 20% kept for driving; a two-truck solar carport (about 7.5 kW), in mixed sun and clouds; no generator.
Yes. On days like that, the sun puts back more than you use, so it keeps going as long as the weather holds and the solar is built to keep working in an outage.
Uses 12.1 kWh a dayPeak 4,810 watts
Running: The essentials, plus central air, for 7 days.
Power: An electric pickup with the biggest battery (about 200 kWh), 20% kept for driving; no solar; no generator.
Not for 7 days. The battery lasts about 4.4 days. For longer, add a generator, more battery or a shorter list. One catch: with everything on at once, it pulls about 11,610 watts, more than this battery setup usually delivers (9,600 watts). Run the big things one at a time.
Uses 32.9 kWh a dayPeak 11,610 watts
Running: The essentials, plus one window A/C and a well pump, for 7 days.
Power: A wall-mounted home battery (about 13.5 kWh), 20% kept in reserve; no solar; a 5,000-watt portable generator.
Yes, with the generator. The battery lasts most of a day. After that, the generator runs about 4.2 hours a day to keep up, instead of 24.
Uses 13.1 kWh a dayPeak 6,510 wattsGenerator: 4.2 hrs a day
Running: The essentials, for 3 days.
Power: No battery; no solar; a 5,000-watt portable generator.
The generator has to run around the clock, about 24 hours a day.
Uses 4.9 kWh a dayPeak 3,660 wattsGenerator: all day
Running: The essentials, plus a freezer, central air, an electric water heater, an electric oven and an electric dryer, for 3 days.
Power: An electric pickup with the biggest battery (about 200 kWh), 20% kept for driving; no solar; no generator.
Not for 3 days. The battery lasts about 2.8 days. For longer, add a generator, more battery or a shorter list. One catch: with everything on at once, it pulls about 23,710 watts, more than this battery setup usually delivers (9,600 watts). Run the big things one at a time.
Uses 51.4 kWh a dayPeak 23,710 watts
Send us your numbers and we'll come back with what it would take at your place: battery, solar, generator and the hookup.
We answer every message ourselves.
Typical figures. Your own appliances may use more or less, so check the labels.
| Appliance | Watts running | Watts to start | Hours a day | kWh a day |
|---|---|---|---|---|
| Refrigerator | 150 | 1,200 | 10 | 1.5 |
| Chest or upright freezer | 100 | 800 | 10 | 1 |
| LED lights, about 10 bulbs | 100 | – | 6 | 0.6 |
| Wi-Fi, phones and a laptop | 60 | – | 12 | 0.7 |
| TV | 100 | – | 4 | 0.4 |
| Ceiling or box fans, two | 100 | – | 12 | 1.2 |
| Medical device, like a CPAP | 50 | – | 8 | 0.4 |
| Microwave | 1,200 | – | 0.25 | 0.3 |
| Coffee maker | 900 | – | 0.2 | 0.2 |
| Window air conditioner, one room | 900 | 2,200 | 8 | 7.2 |
| Well pump | 1,000 | 3,000 | 1 | 1 |
| Central air conditioning | 3,500 | 9,000 | 8 | 28 |
| Electric water heater | 4,500 | – | 2.5 | 11.3 |
| Electric range or oven | 2,500 | – | 1 | 2.5 |
| Electric clothes dryer | 5,000 | – | 0.75 | 3.8 |
| Power source | Stored power | Most it delivers at once | Fastest it refills from a generator |
|---|---|---|---|
| Golf cart, 48-volt lithium | About 5.4 kWh | About 6,000 watts, with a large inverter | About 2.8 kW |
| Two golf carts | About 10.8 kWh | About 6,000 watts | About 5.6 kW |
| Wall-mounted home battery | About 13.5 kWh | About 11,500 watts | About 5 kW |
| Electric pickup | About 100 to 200 kWh | About 9,600 watts (the low end; some trucks deliver more) | About 7.7 kW on a home charger |
Planning numbers, not a design. See golf cart backup power, powering your house with your truck and solar carport vs. generator for the details.
Add up what you want to keep running and how many hours a day each one runs. That gives you kWh per day, the size of the tank. Then add up the watts of everything that could run at once, plus the jolt a fridge, pump or air conditioner takes to start. That gives you peak watts, the size of the pipe. The battery has to hold enough kWh, and the inverter or generator has to handle the peak watts.
kW (kilowatts) is how hard you're pulling power right now, like the speed of the water through a hose. kWh (kilowatt-hours) is how much you use over time, like the gallons in the bucket. Batteries are sized in kWh; inverters and generators are sized in kW.
So the generator runs a few hours to refill the battery and then shuts off, instead of running all day at a light load. Less fuel, less noise, less wear.
Only if the system is built for it. Most grid-tied solar shuts off when the grid goes down. To keep charging a battery or vehicle in an outage, the system needs backup equipment approved for that setup. Check with the maker of your vehicle or battery before counting on it.
It's a planning estimate built on typical appliance numbers. Real use depends on your appliances, the weather and how you live. Check the labels on your own appliances, and have a licensed electrician size the final system.